The satellite antenna is the base portion of the antenna. It looks like this-
As for improving reception, I don't think it's possible. Satellite reception is near vertical, unlike radio which is horizontal. Trees, buildings, bridges, even clouds will effect reception. The OEM antenna is located in about the best possible place for minimal interference.
As for which wire the base is, I am unsure. Hopefully an audiophile can jump in here with that info.